for spatial mobility that other ethnic groups in the ghettoes once had, and, if so, how does this feeling affect their attitudes toward the ghetto as a physical space, toward their own community, and toward the world outside the ghetto? The interrelationships of poverty, crowding, and political behavior are admittedly among the most difficult relationships to investigate. In the absence of reliable knowledge, however, it is at least useful to be aware of the extent to which unverified hypotheses and myths often guide public policy. Perhaps the most glaring example is the opinion that elites of poor and densely populated countries, such as China, do not value human life to the extent that political elites do in more prosperous, less densely populated regions of the globe, and that their elites are, therefore, likely to behave in irrational and violent ways in international politics. Such an unverified assumption underlies some of the estimates of potential Chinese aggressiveness. 10. The growth of population has often been accompanied by government policies which make use of the distribution of people within a society to bring about other government aims. A population policy, for example, may be directed at extending political control over an area that is not densely populated—as the United States Government intended in the 19th century when it used population growth through migration as a means of promoting its western land policy. Similarly, the Soviet Union is encouraging the settlement of portions of central Asia as part of an overall security policy. Governments continue to use immigration policies to affect the internal distribution of political power among various ethnic groups. One ethnic group may use its position in government to promote immigration legislation directed at asserting its political dominance over other ethnic groups—as in the policies of South African white racist regimes or the Guyana policy of increasing the black population in proportion to East Indians.* In this connection it is useful to call attention to the need for political scientists to study the political consequences of internal population movements—not only of rural-urban migration, but also the movement of people from one ethnic group into areas in which other ethnic groups predominate. What new patterns of intergroup relations are created? To what extent do sentiments against "outsiders" emerge? What are the effects on national integration? If regional economic differentials grow in newly developing areas, will people migrate from one part of the country to another as they did in the United States and Europe, or will ethnic divisions prove to be a barrier to *According to the New York Times, July 6, 1969, the East Indian opposition in Guyana is fearful that the Prime Minister, a Negro, is planning to populate the interior of the country with Negroes imported from the West Indies, partly to develop large underdeveloped portions of the country, but also in order to change the political balance between Indians and Negroes.ultural or historical data.